This paper reviews the literature on the nature of the Hispanic paradox and the major explanations provided for it. We conclude by suggesting directions for future research. DATA IDENTIFICATION AND STUDY SELECTION: Articles were selected by a systematic review procedure using Medline (1966 through 1999) and Sociological Abstracts (1963 through 1999), as well as focused searches on specific diseases or factors believed to influence Hispanic health. For the past twenty years there has been widespread evidence of an Hispanic paradox in the United States, in which most Hispanic groups are characterized by low socioeconomic status, but better than expected health and mortality outcomes. A closer look reveals variations by age, gender, Hispanic subgroup, acculturation, country of birth, and cause of death. Possible under-reporting of Hispanic deaths, "salmon bias" and healthy migrant effects, and risk profile may contribute to, but do not explain, the paradox. The reasons for this paradox are likely to be multifactorial and social in origin. Empirical studies should be conducted on the protective effects of immigrant status, identification with a subculture, interaction between acculturation and socioeconomic status, and supportive aspects of Hispanic culture.